1. Field of the Invention
This invention relates generally to direct current motor control. More particularly this invention relates to a circuit for continuous control of a direct current motor capable of rotating in opposite directions and being energized from a single power source.
2. Description of the Prior Art
A variety of circuits exists wherein direct current motors are controlled in a bridge circuit arrangement by means of a single voltage source, permitting the motor to rotate in either a clockwise or counterclockwise direction. Such prior art circuits conventionally use switching type semiconductor devices, in particular switching type transistors. The switching devices of the prior art are arranged in the four bridge paths and open or close in pairs. This brings about a reversal of polarity of the applied voltage on the terminals of the motor so that the motor can be driven in either rotational direction.
In such prior art circuits, where the noise levels introduced by switching transients did not outweight the need for high efficiency in delivering power to the direct current motor, the use of conventional switching type transistors was satisfactory For certain applications however, a direct current motor control circuit is required which can be characterized by high efficiency, excellent linearity, low noise levels and small physical size.